The compound of formula (I) is an Ang II receptor antagonist. Its chemical name is 2-butyl-4-chloro-1-[2′-(1H-tetrazol-5-yl)-1,1′-biphenyl-methyl]-imidazole-5-carb-oxylic acid, 1-[(isopropoxy)-carbonyloxy]methyl ester. Chinese Patent CN101024643A describes the structure, and its use as antihypertensive drugs.

As regards to the solid physical properties of the compound of formula (I), the patent document of CN101024643A discloses that it is a white solid, and its melting point is 134.5-136° C. However, CN101024643A dose not disclose the crystalline structure of the compound of formula (I).
The crystal state of a compound may be important when the compound is used for pharmaceutical purpose. Compared with the amorphous solid, the solid physical properties of the crystalline compound may change, which may affect its whole process of pharmaceutical use. For example, the fluidity of the solid may affect the degree of difficulty of material treatment in the process of drug preparation. The powdery solid compounds with poor fluidity may not be suitable for the subsequent preparation of formulation. The solubility of the solid in water may affect the absorption, efficacy, metabolism of drugs and the preparation of liquid formulation, such as syrups. The solid form of a compound may also affect its compressive behavior and its storage stability. For example, a crystalline compound may overcome the disadvantage of an amorphous compound that it is easy to absorb moisture and metamorphose, and it has good light stability and thermal stability.
The solid physical properties mentioned above may be affected by the confirmation and orientation of the crystal cell, which may determine the specific crystal form of a substance. The crystal form mentioned has a thermodynamic behavior which differs from amorphous substance or another crystal form. The specific crystal form may be distinguished from amorphous compound or another crystal form by determining the thermal property using a melting point instrument, thermogravimetric analysis (TGA), or differential scanning calorimetry (DSC) in laboratory. Moreover, a specific crystal form has specific spectroscopic properties. For example, the specific crystal forms can be characterized by the data of powder X-ray diffraction pattern and infrared spectrum.
In addition, the preparation of crystalline compounds is one of important methods to purify the amorphous compounds in a large scale. So the crystalline compound of formula (I) and its preparation have crucial practical significance.